American Family Vision Clinic Logo
Conrad, Joseph Samuel; Mitchell, G. Lynn; Kulp, Marjean Taylor

Vision Therapy for Binocular Dysfunction Post Brain Injury

publication date
see more



To prospectively evaluate the effectiveness of home-based computer vergence therapy for the treatment of binocular vision disorders in adults at least 3 months after an acquired brain injury.


Eligibility criteria included presence of binocular dysfunction characterized by receded near point of convergence (≥6 cm break), insufficient positive fusional vergence at near (failing Sheard’s criterion or <15△ blur or break), insufficient negative fusional vergence at near (<12△ blur or break), and/or reduced vergence facility at near (<15 cycles per minute with 12△BO/3△BI). Participants were prescribed 12 weeks of home-based computer vergence therapy. Phoria (cover test), negative fusional vergence, positive fusional vergence, near point of convergence, vergence facility, and symptoms (convergence insufficiency symptom survey [CISS]) were assessed at baseline and after 4, 8, and 12 weeks of prescribed therapy. ANOVA was used to evaluate change in each measure. Percentage successful was also determined.



Nineteen participants were enrolled (mean age 45.4 ± 12.9 years); six participants were lost to follow-up. Baseline findings were orthophoria at distance, 7.2△ exophoria at near, near point of convergence break = 17.5 cm, near point of convergence recovery = 21.8 cm, negative fusional vergence = 12.3△, positive fusional vergence blur = 8.4△, vergence facility = 3.9 cycles per minute, and CISS = 32.1. ANOVA showed a statistically significant improvement for near point of convergence break (p = 0.002) and recovery (p < 0.001), positive fusional vergence blur (p < 0.0001), break (p < 0.0001), and recovery (p < 0.0001), negative fusional vergence blur (p = 0.037), break (p = 0.003), and recovery (p = 0.006), vergence facility (p < 0.0001), and CISS (p = 0.0001). The percentage of patients who were classified as “successful” or “improved” was 69% for near point of convergence (<6 cm or decrease of ≥4 cm), 77% for positive fusional vergence (>15△ and passing Sheard’s criterion or increase of ≥10△), 77% for negative fusional vergence (≥12△ or increase of ≥6△), 62% for positive fusional vergence and near point of convergence composite, and 92% for vergence facility (15 cycles per minute or increase of 3 cycles per minute).


The majority of participants who completed the study experienced meaningful improvements in signs and symptoms.


Such a nice optician. My grandson is only 4 and needs glasses. We were so sad, but he explained the issues, and we will follow up as he suggested.

Anna P.

I had such a good experience with the clinic. Very friendly staff and doctor, did not have to wait for long to be called, and was treated respectfully. Thanks, American Family.

June S.

Dr. Zurcher has gone above and beyond what any other eye doctor has ever done to figure out what is going on with my eyes. Very happy with American Family Vision.

Christine R.

Family Vision Clinic changed our lives! My daughter was frequently car sick, and she was getting headaches every day, often painful enough that they brought her to tears. We saw a string of doctors and therapists, but we made no progress. Finally, we found Dr. Levi Zurcher and his eye therapist Rain. After ten weeks of eye therapy my daughter no longer gets headaches, and she no longer gets car sick. Daily tears are a thing of the past. I really can’t say enough about this clinic. It was fascinating to watch Dr. Zurcher work. For the first time, someone who knew what they were doing was intently studying my daughter, really trying to figure out all of her eye issues, and his therapist Rain is one of the most patient and lovely people that I’ve ever had the good fortune to meet. We’re finished with eye therapy—yay!—and I have switched to American Family Vision Clinic for all of my family’s other eye health needs.

Lars Wulff

Very professional, yet kind and helpful. They do what they can to make the appointment comfortable. I was running a bit late, I made sure ti call. They were able to switch me with a patient who was already there, they treated me with respect, and helped my son have confidence by getting him the eye care he needed that day. Thank you so much! Would recommend to anyone. It's a blessing that they care enough to work with people who have all different types of insurance from work to state coverage.

Justin E.

The staff is friendly. The Doc is very knowledgeable. The office is family friendly and everyone is so patient with the little ones.

Amy Fagerness
1 2 3



Beyond LASIK: Discovering New Vision Correction Techniques

According to the American Society of Cataract and Refractive Surgery (ASCRS), there were approximately 1.8 million LASIK procedures performed in […]

Read More

[mbv name="token-practice-city"] eye doctor explains how to get rid of under eye bags

As a local optometry clinic, we often get asked how to get rid of under eye bags. Many people have […]

Read More

Olympia Optometrist's Guide to Understanding Pink Eye: Symptoms, Causes, and Treatment

Bacterial conjunctivitis is a prevalent condition globally. In the US, it affects 135 out of every 10,000 people each year, […]

Read More
see all blogs

Contact Us To Amplify Your EyeCare

Working Hours

Monday - Thursday
8:00 am - 5:15pm
400 Yauger Way SW. Bldg 1, Ste A Olympia, WA 98502
Website Accessibility Policy
Safety protocols page
phone-handsetarrow-uparrow-right linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram